Filter out content in sync that is currently unhandled (#198)

I had a look at sync.cpp and checked which parts of the sync response
are currently handled and which not. As I think it is unnecessary to let the 
unhandled data be transmitted without being handled I added these filters.

In the same term I increased the timeout server-side to 30s as Riot
defaults to this value as well. Especially now when a lots of presence-updates 
are not send anymore this value is more relevant.

It is now also possible to use a filter that is defined in`client/sync_filter`.
Advanced users might want to set an own filter here.

[ci skip]

1 files changed, 3 insertions, 0 deletions

diff --git a/include/MatrixClient.h b/include/MatrixClient.h

index df21ccdb..66b30dce 100644
--- a/include/MatrixClient.h
+++ b/include/MatrixClient.h
@@ -159,4 +159,7 @@ private:
 
         // Token to be used for the next sync.
         QString next_batch_;
+
+	// filter to be send as filter-param for (initial) /sync requests
+	QString filter_;
 };